JPH02250236A - Plasma display device - Google Patents

Abstract

PURPOSE:To have light emission display motion at high contrast ratio while an aux. discharging means is furnished, by performing aux. discharging motion during display discharge motion period through emitting of electric charges one by one. CONSTITUTION:A plasma display device as per present invention includes No.1 electrode 3, No.3 electrode 5, dielectric substance layer 6, No.2 electrode 7, and fluorescent substance film 10. That is, the No.3 electrode 5 is installed on the inner surface of a back face base board 4 made of glass, while the No.2 electrode 7 as a cathode on stripe is installed on the surface of the dielectric substance layer 6 enclosing this No.3 electrode 5 in such an orientation as crosswise the No.1 electrode 3. At the stage of trigger discharge, a number of No.2 electrodes 7 are scanned with negative pulses in linear sequence. Positive wall charges produced by trigger setting are trigger discharged one by one between mating electrodes associate with the linear sequential scanning with neg. pulses. Even through trigger setting and trigger discharge are repeated over the whole dotted discharge zone 9 on a display panel, it is aux. discharge using wall charges and very weak to provide very low value even as the backdrop brightness permitting easy achievement of a contrast ratio of 100/1 or more.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides dot-shaped discharge areas at each three-dimensional intersection of a large number of striped electrodes arranged in a matrix, and phosphors provided in each discharge area. The present invention relates to a plasma display device in which a film is excited and emitted light by ultraviolet light generated in the discharge region.

2. Description of the Related Art A plasma display device in which a large number of striped electrodes are arranged in an XY matrix and dot-shaped discharge areas are set at the three-dimensional intersections of the striped electrodes is configured such that the discharge areas are not delayed by the arrival of information pulses for light emitting display. Display discharge operation must be performed reliably.If charged particles such as ions or electrons that smooth the start of discharge are not present in the discharge space, the start of discharge will be delayed or erroneous discharge will occur. In order to overcome this problem, in DC lighting type plasma display devices, this kind of problem is solved by generating an auxiliary discharge called a pilot discharge.

Such an auxiliary discharge method, as disclosed in Japanese Patent Publication No. 61-30279, etc., can be performed by utilizing the stray capacitance between the anode and the cathode, and the discharge is always weak regardless of the presence or absence of an information pulse. Since the configuration is such that the auxiliary discharge is scanned, the display discharge operation can be started without delay even if the display information pulse arrives at the discharge area at the position where the discharge occurs.

This auxiliary discharge method is easier and cheaper to implement than other methods in terms of the structure of the display panel and its drive circuit, so it is suitable for plasma display devices currently in practical use.
It is mainly used in plasma display devices that produce an orange luminescent display using neon gas discharge.

Problems to be Solved by the Invention On the other hand, the market has seen the emergence of plasma display devices that can emit light in colors other than orange due to conventional neon discharge, such as monocolor or multicolor emitting display such as green, amber, or white. The voices of desire are strong.

Such a plasma display device can basically be realized by using a xenon-based gas with a high ultraviolet emissivity as a discharge gas, and by exciting a phosphor film in the discharge area to emit light with the ultraviolet light generated during display discharge. .

However, even in a configuration in which the phosphor film is excited to emit light, the gas discharge operation is the basis, so an auxiliary discharge means is required to obtain smooth display operation.

Therefore, it is possible to apply the auxiliary discharge scanning method using stray capacitance as described above, but since the brightness of the light emitted by the auxiliary discharge, that is, the background brightness, is quite bright,
The display contrast ratio (display brightness/background brightness) is low, making the luminescent display difficult to read.For example, the contrast ratio of a conventional orange luminescent plasma display device that uses neon discharge is 10:1. The contrast ratio in a phosphor film-excited light emission type plasma display device is 2.5 to 6:1.According to experiments, the light emission display can be clearly distinguished if the contrast ratio is 10=1 or more.

At a contrast ratio of 6:1, discrimination is possible, but it is quite difficult to see, and at a contrast ratio of 2.5:1, discrimination is almost impossible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a phosphor film excitation type plasma display device which is equipped with an auxiliary discharge means and is capable of achieving a light emitting display operation with a high contrast ratio.

The reason for the low contrast ratio of phosphor film-excited plasma display devices using conventional auxiliary discharge means is due to the mechanism of ultraviolet radiation generated by gas discharge. That is, as schematically shown in FIG. 5(a), the brightness of visible light emission during the display discharge period BC during which an information pulse is applied follows the course of AFD, whereas the brightness of ultraviolet light emission follows the course of the discharge. It is high for a few microseconds during the transient period immediately after the start, but then it shifts to a stabilized glow discharge and rapidly decreases, so the AF
' Follow the progress of D=. Therefore, if the period during which the auxiliary discharge pulse is applied is BE, then the contrast ratio in the conventional orange-emitting plasma display device is ABCD/A.
BEF masu becomes 10/1.

On the other hand, in a plasma display device with a phosphor film that utilizes ultraviolet light emission, ABCD7ABEF-/''=2.5 to 6/1, which is inevitably low.

Means for Solving the Problems According to the present invention, there is provided a three-dimensional intersection between a striped first electrode group arranged in one direction and a striped second electrode group arranged in a direction intersecting the same electrode group. A dot-shaped discharge region is set in the discharge region, a phosphor film is provided in each of the discharge regions, and a third electrode covered with a dielectric layer is connected to the second electrode.
An electrode assembly provided on the back side of the electrode group is hermetically sealed in an envelope together with a discharge gas containing xenon, and a display discharge operation is performed between the first electrode group and the second electrode group. The third electrode is used to charge the exposed surface of the dielectric layer during a vertical blanking period during which the display discharge operation is not performed, and the charge is assisted by sequential discharge of the charge as the second electrode group is sequentially scanned during a display discharge operation period. Operate the discharge.

Charging of the exposed surface of the working dielectric layer can be obtained by applying one trigger pulse between the first and third electrode groups during the vertical blanking period. The wall charge thus obtained is distributed between the electrodes of the second electrode group, but
The electrode group is line-sequentially scanned at a negative potential (in the process, a discharge is sequentially generated between the electrodes and the same electrode), and charged particles necessary for display discharge are supplied to the discharge space.

This auxiliary discharge is extremely weak compared to the conventional auxiliary discharge generated between the first electrode (anode) and the second electrode (cathode), and its brightness is 5th compared to the brightness of display discharge light emission. The relationship is as shown in (b) of the figure. That is, the time-integrated value A″BE″ of the light-emitting brightness of the auxiliary discharge is extremely small compared to the time-integrated value ABCD′ of the light-emitting brightness of the display discharge, and the contrast ratio ABCD”/A″BE”=10.
It becomes possible to achieve a ratio of 0/1 or more.

Embodiments Next, the present invention will be explained in more detail with reference to embodiments shown in the drawings.

FIG. 1 shows a cross-sectional structure of a plasma display device according to the present invention at one display position, in which a film-like light-shielding mask 2 is provided on the inner surface of a front substrate 1 made of glass, and a light-transmitting mask 2 is arranged in the − direction. A first electrode 3, which is a striped anode, is attached. Further, on the inner surface of the back substrate 4 made of glass, a third
A dielectric layer 6 is provided with an electrode 5 and covers the third electrode 5.
A second electrode 7, which is a striped cathode, is arranged on the surface of the electrode 7 in a direction intersecting the first electrode 3. First electrode 3
and the second electrode 7 are separated by a dielectric partition 8 as a spacer, and a dot-shaped discharge region 9 is set at the three-dimensional intersection of the first electrode 3 and the second electrode 7. A discharge gas containing xenon is filled in the discharge region 9, and a phosphor film 10 for color display is attached in the form of a dot on the surface of the first electrode 3.

The third electrode 5 is made of a conductive material having a low resistance value, such as metal such as gold, nickel, aluminum, copper, or silver, or ITO.
The material is a metal oxide such as, and is formed substantially in the form of a film over the entire display surface. The dielectric layer 6 is obtained by printing a thick film of a lead borate-based low septum glass paste containing a dielectric material such as aluminum oxide or silicon oxide, and firing it, and has a film thickness of 40 to 60 microns. is formed. The partition wall 8 is finished to a thickness of 100 to 200 microns by repeating thick film printing of insulating paste. The discharge gas is a binary mixed gas containing helium and xenon, a ternary mixed gas, or a single xenon gas sealed at a pressure of 10 to 500 Torr depending on the gas composition.

When the above-described auxiliary discharge and display discharge are performed using a display panel configured in this way, the phosphor film 10 is excited to emit light by the ultraviolet rays 12 emitted by the plasma discharge 1, and the phosphor film 10 emits light at a wavelength unique to the phosphor. is converted into visible light 13 for color display.

2 and 3 schematically show the process of auxiliary discharge, and FIG. 4 shows its waveform and timing chart. In the trigger setting stage, as shown in FIG. 2, a trigger pulse vT of 300 to 400 Vp-p is applied between the first electrode 3 and the third electrode 5 during the vertical blanking period. The voltage polarity of the applied pulse is set so that the third electrode 5 side is negative. Then, a positive wall charge is generated on the exposed surface of the dielectric layer 6.

At the stage of trigger discharge, a large number of second electrodes 7 are scanned line-sequentially with a negative pulse V. The positive wall charge generated by the above-mentioned trigger setting is caused by line-sequential scanning by the negative pulse.
Trigger discharge (auxiliary discharge) is performed sequentially between corresponding electrodes. That is, charged particles are generated in the discharge region in preparation for the arrival of the input pulse for light emission display. In FIG. 4, a large number of second electrodes are indicated by initials, and the first electrodes are indicated by A.

Even if the trigger setting and trigger discharge are repeated over the entire dot-shaped discharge area of the display panel,
Since such auxiliary discharge using wall charges is extremely weak, the background luminance is also extremely low, and a display contrast ratio of 100/1 or more can be easily achieved.

Next, to explain the configuration of each part and the auxiliary discharge operation with specific numerical examples, the striped first electrode is made of ITO and arranged on the front substrate with a pitch of 0.3 mm + 64 mm.
0 can be formed. In addition, a striped second
400 electrodes can be formed on the back substrate at an array pitch of 0.36- by thick film printing using nickel as a material.

Then, a dot-shaped phosphor film that emits green color is provided in the discharge area of the three-dimensional intersection of the picture electrode, and 400 x 640 = 25
A color plasma display can be made with 6,000 display units.

The third electrode disposed on the rear substrate can be formed by thick film printing and baking, and aluminum can be used as the material. The dielectric layer covering the third electrode can be formed by printing a thick film of lead borate low-melting glass containing aluminum oxide powder to a thickness of 60 microns and firing it, and the dielectric partition wall can be formed by repeatedly printing a thick film of insulating paste. It can be finished to 130 microns. The discharge gas is a He-Kr-Xe ternary mixed gas of 4QQTorr and Xe alone at 70T.
Two types were tested: the orr one. The trigger pulse used for trigger setting is 350V P-P.
It is.

The volume ratio of the He-K r-X e ternary mixed gas is He
It can be set to 93%, Kr5%, and Xe2%.

The capacity ratio of Xe can be selected within the range of 2±0.5%.

The contrast ratio of such a plasma display device is as shown in the table below, and this dramatic improvement is the result of applying a unique auxiliary discharge method.

Effects of the Invention Since the present invention is configured as described above, it is possible to obtain a phosphor film excitation type plasma display device which is equipped with an auxiliary discharge means and can obtain a light emitting display operation with a high contrast ratio.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a plasma display device embodying the present invention at the 1 display position, FIGS. 2 and 3 are side sectional views for explaining the operation of the device, and FIG. 4 is an explanation of the same operation. The timing chart of the signal in Fig. 5 (a), (
b) is an emission brightness characteristic diagram for explaining the mechanism of ultraviolet radiation. 1... Front substrate, 3... First electrode, 4
... Rear substrate, 5 ... Third electrode, 6.
...Dielectric layer, 7...Second electrode, 9...
...discharge area, 10...phosphor film. Name of agent: Patent attorney Shigetaka Awano and 1 other person / - Front @ Slope 3 - Ta F9 - Electrode 4 - Back board, 5-1 3rd electrode B - Dielectric 0. layer 7 - 2nd i paper 9 −°−Charcoal Den αKorokufO−11 Fluorescent Hole Closed Diagram

Claims (1)

[Claims] A dot-shaped discharge area is set at a three-dimensional intersection between a first striped electrode group arranged in one direction and a striped second electrode group arranged in a direction that intersects the same electrode group. An electrode structure including a phosphor film provided in each region and a third electrode covered with a dielectric layer provided on the back side of the second electrode group is sealed in an envelope together with a discharge gas containing xenon. and charging the exposed surface of the dielectric layer using the third electrode during a vertical blanking period during which no display discharge operation is performed between the first electrode group and the second electrode group. . A plasma display device characterized in that an auxiliary discharge operation is performed by sequentially releasing the charges as the second electrode group is sequentially scanned during a display discharge operation period.